COM July 2012

This is a 25-year-old Caucasian female who presented with an expansile and well-demarcated radiolucency in the right posterior mandible (Figure 1). The panoramic radiograph demonstrates a well-defined unilocular radiolucency with a scalloped border below teeth #s 28-30. The lesion is focally eroding and pushing down on the inferior border of the mandible. The lesion is of unknown duration and the associated teeth are vital.

Figure 1. This panoramic radiograph was taken at first clinical presentation. Note the well-demarcated unilocular radiolucency with scalloped border involving area of teeth #s 28-30. Also note the thinning of the inferior border of the mandible with inferior expansion.

The patient’s past medical history is negative for any significant disease or risk factors. Patient report no known allergies to drugs or foods.

Patient presented on referral from her general dentist after noticing mild expansion of the right buccal vestibule during a routine dental examination. The area was firm and non-tender to palpation. A cone beam CT study was obtained, which revealed a well corticated, well circumscribed radiolucent lesion in the area and in a very close proximity to the inferior alveolar canal.

Figure 1. This panoramic radiograph was taken at first clinical presentation. Note the well-demarcated unilocular radiolucency with scalloped border involving area of teeth #s 28-30. Also note the thinning of the inferior border of the mandible with inferior expansion.

Treatment

The patient underwent enucleation of the lesion through a buccal corticotomy. Multiple fragments of “fleshy” pink tissue were removed from the site. The surgical defect was curetted and cleaned with a rotary instrumentation. The wound was irrigated with sterile solution and the soft tissues were re-approximated and closed with 3-0 chromic sutures.

Excisional Biopsy

Histologic examination reveals multiple pieces of decalcified hard and soft tissue composed of a neoplasm of spindle-cell origin. This neoplasm is made up of predominant acellular and hyalinized tissue in the center and loose and myxoid tissue at the periphery (Figure 2). The latter is made up of compact and short bundles of spindle shaped cells (Figure 3). By Immunohistochemistry (IHC) stain, the spindle-shaped cells are positive with antibody to S-100 protein (Figure 4). The IHC stain also identified small dendritic type cells. Also present are cells with palisaded nuclear morphology (Figure 3). This neoplasm is surrounded by calcified bone with viable osteocytes.

Figure 2. Low power (x40) H & E stained section illustrates a predominantly acellular and hyalinized tissue in the center and loose and myxoid tissue at the periphery. The latter is made up of compact and short bundles of spindle shaped cells.

Figure 3. Higher power (x100) H & E stained section illustrates at a higher power the compact and short bundles of spindle shaped cells.

Figure 4. Higher power (x100) immunohistochemistry stained section illustrates the spindle-shaped cells to be positive with antibody to S-100 protein.